Braked ball and socket support for bucket attachment



Feb. 3, 1970 c. 5 www BRAKE]; BALL AND SOCKET UiPORT FOR BUCKET ATTACHMENT Filed March 8,

2 Sh'ets-S heet 1 INVENTOER CARL F. NOVDTNY W Oa ATTORNEY Feb. 3, 1970 c. F. N O'IVOTNY 3,493,135

BRAKED BALL AND SOCKET SUPPORT FOR BUCKET ATTACHMENT Filed March 8, 1968 2 Sheets-Sheet 2 INVENTOR CARL F. NOVOTNY %4fi% ATTORNEY U.S. Cl. 214-147 6 Claims ABSTRACT OF THE DISCLOSURE A support for the bucket attachment of a stick clam excavator includes a bracket comprising spaced arms carrying facing, laterally spaced socket segments; and a ball on the upper end of the bucket attachment is received between the segments. Each segment carries a hydraulic braking cylinder having a piston and a brake shoe adapted to be moved by the piston against the ball in response to pressure in the cylinder. The cylinders and shoes are aligned along an axis transverse to the plane of movement of the stick so that the attachment is relatively free to pivot in the plane of the stick, this freedom being enhanced by the pistons and brake shoes being relatively free to rotate in the cylinders. The stick is on a boom which is actuated by means of hydraulic hoist cylinders, and the pressure ends of the hoist cylinders are hydraulically linked to the brake cylinders so that the braking force on the ball is directly proportional to load.

BACKGROUND OF THE INVENTION This invention relates, but is not necessarily limited to, a unique support for the bucket attachment of a stick clam excavator. In machines of this type, a bucket attachment is supported at the end of a live stick so that the stick can be used to force the bucket downwardly into the material being excavated.

The support for the bucket attachment of a stick clam excavator should fulfill a number of important requirements. It should, of course, provide sufiicient rigidity and strength to allow the stick to be used to force the bucket attachment downwardly. It should allow the bucket attachment to pivot relatively freely in the plane of movement of the stick so that the attachment will remain vertical during raising and lowering movements. It should also allow for some transverse movement of the bucket attachment to compensate for ground irregularities encountered during digging; but this movement should be limited to minimize transverse buckling during digging and lateral oscillations during swinging movements. The attachment should be as simple as possible, both to minimize cost and to minimize the possibility of malfunction or damage after long or hard use.

Heretofore, it has been conventional to support the entire bucket attachment on a transverse pin at the end of the stick to allow free movement in the plane of the stick, and then to provide a second pin perpendicular to the first to provide for transverse movement. This arrangement is not entirely satisfactory, however, since the transverse movement is not limited and buckling and oscillation present serious problems. To overcome these and other problems, improved supports have been proposed which incorporate means to provide for desirably limited transverse movement; and two highly satisfactory constructions of this type are shown and described in the copending applications of George W. Mork for Rocker Support for Bucket Attachment, Ser. No. 702,708, filed Feb. 2, 1968, and of George W. Mork and Carl F. Novotny for Cable Support for the Bucket Attachment Li ited States Patent O 3,493,135 Patented Feb. 3, 1970 of a Stick Clam Excavator or the Like, Ser. No. 708,619, filed Feb. 27, 1968.

It has also been proposed to mount buckets or grabs by means of a ball and socket support to provide for movement in all directions using a single connection, but a ball and socket type of connection presents much the same problem as a two-pin connection in that transverse movement is not properly limited. Any attempt to tighten the ball and socket connection as a whole to limit transverse movement would, of course, also undesirably restrict movement in the vertical plane of the stick.

Summary of the invention It is the general object of this invention to provide a novel and improved support for the bucket attachment of a stick clam excavator or the like which fulfills all of the noted requirements, which is strong enough to be adaptable for use with relatively large machines, but which is still relatively simple and inexpensive to manufacture and maintain.

One specific feature of the invention is the use of a ball and socket type of support in combination with brakes which allow relatively free pivotal movement in the plane of the stick while allowing but clearly restricting transverse movement.

Another particular feature of the invention is the use of a hydraulically actuated braking system, useful in other types of supports as well as in the ball and socket arrangement shown, in which a brake cylinder and a main hoist cylinder are linked so that braking force is made proportional to load.

Other objects, features and advantages will appear from the description of the preferred embodiment which follows.

Brief description of the drawings FIG. 1 is a side view in elevation, with parts shown broken away and in cross section, showing a bucket attachment connected to the tip of a stick by means of a support constituting a preferred embodiment of this invention,

FIG. 2 is an enlarged fragmentary view in cross section through the plane 22 shown in FIG. 1, and

FIG. 3 is a schematic view on a reduced scale of a stick clam excavator incorporating the support of FIGS. 1 and 2.

Description of the preferred embodiment Referring first to FIG. 3, the excavator shown therein is generally conventional and includes a working frame 1 which is revolvably mounted on a crawler base 2. An angled boom 3 is footed on the frame 1 and is raised and lowered in a vertical plane by means of a pair of parallel hydraulic hoist cylinders 4, only one of which can be seen. A stick 5 is pivotally mounted at the tip of the boom 3 to be movable in the same vertical plane and is actuated in this plane by means of a hydraulic dig cylinder 6. A bucket attachment designated generally by the reference numeral 7 is mounted on the tip or forward end of the stick 5 by means of the support which will be described below.

As indicated, the machine of FIG. 3 is generally conventional, and the construction and operation of such machines is well known to those skilled in the art. As a result, the machine is not shown and will not be described in detail. More detail showings and descriptions of such machines may be found in US. Patent No. 2,755,946, issued July 24, 1956 to J. I. Bevan, and in the copending application of George W. Mork and Carl F. Novotny for Hydraulic Actuated Clamshell Bucket Attachment for Stick Clam Excavators or the Like, Ser. No. 702, 728, filed Feb. 2, 1968. It should also be noted that while the support of this invention is particularly designed for use in such machines for connecting a bucket attachment to the end of a live stick which is in turn mounted on a live boom, it might be equally useful in other machines or in other applications in which a bucket attachment is connected directly to the end of a boom or equivalent element. The terms stick and stick clam excavator as used herein, therefore, are intended to encompass equivalent elements, machines and applications.

With the exception of the neck and swivel arrangement which will be described, the bucket attachment 7 is generally the same as that shown and described in the aforesaid copending application of George W. Mork and Carl F. Novotny, Ser. No. 702,728, to which reference may be had. It includes a double acting hydraulic cylinder 8 which has a tubular housing 9 connected to its rod end. A cross head 10, which extends outwardly through vertical slots on both sides of the housing 9, is connected to and movable upwardly and downwardly in response to the extensible and retractable rod (not shown) of the cylinder 8. A pair of bucket halves 11 are pivotally mounted on a common axis 12 at the outer end of the housing 9, and links 13 connected between the ends of the cross head and respective bucket halves 11 serve to open and close the latter.

At the inner or casing end of the cylinder 8 is a neck 14 which is rotatably connected to the casing proper in any suitable fashion. A generally conventional swivel mechanism including a hydraulic motor 15, a driving gear 16 and a driven gear 17, all enclosed in a housing 18, is operable through conventional hydraulic circuitry (not shown) to cause the bucket attachment 7 to be rotated about its vertical or longitudinal axis in what is termed a swivel action.

Although the particular forms of bucket attachment and swivel mechanism shown herein are highly satisfactory and preferred, it will be obvious that other known types of bucket attachments, or equivalent load handling devices or swivel mechanisms, might be used with the support of this invention.

A bracket designated generally by the reference numeral 19 is mounted on the tip of the stick 5 and comprises generally parallel laterally spaced arms 20 suitably attached to the stick 5 at spaced points 21 and 22. The arms 20 are in longitudinal alignment with the stick 5; and being connected thereto at two points are fixed to be movable with the stick 5 in the same vertical plane.

The forward ends of the arms 20 are provided with spherical socket segments 23 which, in the embodiment shown, have rearwardly extending cylindrical base portions 24 fixedly received in tubular collars 25 fixed to the ends of the arms 20. The segments 23 face one another and are in alignment along an axis which is transverse to the plane of movement of the stick 5. The size and angular extent of the segments 23 may be varied, consistent with operational requirements which will be obvious from the following.

A spherical ball 26, which may be hollowed as shown or solid, is fixed to or formed with the neck 14 to be connected to the bucket attachment 7. The ball 26 is received between the socket segments 23 to mount the bucket attachment 7 on the stick 5, it being obvious that the ball and socket mounting arrangement will allow the bucket attachment 7 to pivot about the ball in all directions, at least until the neck 14 or other elements contact the edges of the segments 23 or the stick 5. The segments 23 will of course be engageable with the neck 14 to positively limit transverse movement, and the radial extent of the segments 23 should be selected with the desired degree of movement in mind.

The base portion 24 of each segment 23 is hollowed to define and serve as a hydraulic brake cylinder. Each such cylinder comprises an inwardly opening bore 27 of circular cross section, and a circular cylindrical piston 28 which is reciprocally slidable therein. The pistons 28 are provided with O-ring seals 29 disposed in annular grooves 30 therein. An inlet or pressure port 31 leads through the rear of each base 24 into the bore 27 behind the piston 28 so that hydraulic fluid under pressure may be admitted to drive the pistons 28 inwardly or toward one another. Hydraulic supply lines 32 lead to and communicate with respective ports 31.

Within each bore 27 in front of the associated piston 28 is a generally disc shaped brake shoe 33 formed of any suitable material and having a circular cross section with a slightly concave forward surface which is against and in braking engagement with the surface of the ball 26. Forward or inward movement of the pistons 28 will of course cause the shoes 33 to be pressed harder against the ball 26 and thereby increase their braking force. The bores 27, pistons 28 and shoes 33 are all aligned with one another on the same transverse axis as the segments 23. Both the pistons 28 and shoes 33, because of their circular cross sections, are relatively free to turn or rotate in the bores 27 about this axis, and sufficient clearances should be established to allow such rotation.

Frictional engagement between the ball 26 and the brake shoes 33 will tend to restrict pivotal movement of the bucket attachment 7 in any direction, but there will be significantly less restriction of movement about the axis on which the shoes 33 lie, or in other words in the plane of movement of the stick 5. This is an inherent result of having the shoes 33 on a transverse axis; but the desired action is enhanced in the preferred embodiment because the shoes 33 and cylinders 28 are circular in cross section and relaitvely free to rotate within the bores 27.

The braked ball and socket support shown provides, therefore, for pivotal movement of the attachment 7 in all directions with a single connection; but having the brake shoes 33 located on a transverse axis limits transverse movement to a greater extent while providing desirable relatively free movement in the plane of the stick 5.

The pressure behind the pistons 28 will of course deter mine the braking effect of the shoes 33, and this can be provided for and varied in any suitable fashion. To accomplish the object of limiting movement to a greater degree in all but one desired plane, the hydraulic arrangement shown might be replaced by simple compression springs in the bores 27 behind the shoes 33. It is particularly desirable, however, to have an arrangement in which there is an automatic varying of the braking force in response to load. That is, transverse pivotability is most necessary and desirable when the bucket attachment 7 is first brought down onto the material being excavated, since it is at this point that uneven ground conditions can cause undesirable side stresses or forces. Once the bucket attachment 7 is loaded and being lifted, however, transverse movement should be limited as much as possible to prevent oscillation during swinging.

In the embodiment shown, the desired object of varying braking force to make it directly proportional to load is attained by hydraulically linking the brake cylinders to the lower or pressure ends of the hoist cylinders 4, this connection being shown schematically in FIG. 3 by the dotted line 34. It will be appreciated that the pressure in the pressure ends of the cylinders 4 is at a minimum when the bucket attachment 7 is set down, and increases to a maximum when the attachment is lifted off the ground, the maximum pressure being of course dependent on load. As a result, and because of the hydraulic linking, the pressure behind the pistons 28 is at a minimum to have minimum braking when transverse pivotability is desired. As pressure in the cylinders 4 increases due to lifting of the attachment 7, braking force increases proportionally, and is at a maximum when the attachment 7 is off the ground and being swung to a dump location or back. The greater the load in the bucket, the greater will be the pressure in the cylinders 4 and thus the braking force. At all times, however, the attachment 7 remains relatively free to pivot in the plane of the stick 5 to remain vertical.

In FIG. 3, the hydraulic connection 34 is, as indicated, shown only schematically. It will be understood that the desired linking might be accomplished in any of several ways. The lines 32 might, for example, be connected directly to the casing ends of the cylinders 4 or they might be appropriately connected in a hydraulic circuit so as to carry the same pressure as the cylinders 4. The two inlets 31 may both be linked with one or both cylinders 4 or each with a respective cylinder 4. It is necessary only that there be a hydraulic linking between the pressure end of the hoist cylinders or means and the brake cylinders.

In the particular embodiment shown the two hoist cylinders 4 serve together as a hydraulic hoist means. In other types of machines or other arrangements there might be only one cylinder or one or more cylinders might be differently located or operated. The term hoist means as used herein is intended to cover the arrangement shown or any equivalent hydraulic arrangement which serves to provide a lifting action for a bucket attachment or the like.

The hydraulic linking arrangement shown is particularly satisfactory when used in combination with the ball and socket type of support herein. The same sort of linked hydraulic braking arrangement might, however, also be useful in connection with diiferent types of supports. In a bucket attachment including a separate pin to provide for transverse pivotability, for example, suitable hydraulically actuated brake shoes surrounding the pin or acting against its ends might be linked to a hoist means to limit pivotal movement in response to load in the same manner as shown herein.

A preferred embodiment of the invention has been shown and described herein. Various modifications, however, are obviously possible without departure from the spirit and scope of the invention. These include not only the equivalent arrangements noted above, but others such as reversing the arrangement shown to put the socket segments on the bucket attachment and the ball on the stick, or to put the cylinders and brake shoes in the ball instead of in the socket segments. In view of such possible modifications, it is not intended that the invention be limited by the showing herein or in any other manner except as maybe clearly required.

I claim:

1. In a stick clam excavator or the like having a stick movable in a vertical plane, a bucket attachment, and a support connecting the bucket attachment to the stick,

the improvement wherein the support comprises:

a ball and socket connection between the stick and the bucket attachment allowing relative movement therebetween, said connection including facing socket segments generally aligned along an axis transverse to the plane of movement of the stick and a ball received between the socket segments; and brake shoe means operative between the ball and socket portions of the connection, said brake shoe means being operatively located on the axis of the socket segments.

2. The combination of claim 1 wherein there are two aligned brake shoes disposed on opposite sides of the ball, one operative between each segment and the ball.

3. The combination of claim 2 including hydraulic brake cylinders having bores and pistons movable in the bores and operable against the brake shoes to increase their braking force.

4. The combination of claim 3 wherein the bores, pistons and shoes are of circular cross section; and the shoes are received in the bores and extend outwardly thereof; and the pistons and shoes are rotatable within the bores.

5. The combination of claim 4 including hydraulic hoist means operable to cause the bucket attachment to be lifted; and wherein the brake cylinders and the pressure end of the hoist means are hydraulically linked to make the braking force of the shoes directly proportional to the load on the hoist means.

6. In a stick clam excavator or the like having a stick, a bucket attachment, a support connecting the bucket attachment to the stick, and hydraulic hoist means 0perable to cause the bucket attachment to be lifted,

the improvement wherein:

the support comprises a first member associated with the stick and a second member associated with the bucket attachment, the two members having a connection with one another which allows relative movement between the bucket attachment and the stick; brake shoe means operatively interposed between the two members of the support to be adapted to restrict relative movement therebetween; hydraulic brake cylinder means operative against the brake shoe means to increase the braking force thereof; and a hydraulic link between the hoist means and the brake cylinder means so that the braking force of the shoe means increases in direct proportion to the load on the hoist means.

References Cited UNITED STATES PATENTS 1,237,163 8/1917 Brockett. 1,962,516 6/1934 Mitchell 214--138 3,247,987 4/1966 Lake 214-138 X HUGO O. SCHULZ, Primary Examiner U.S.Cl.X.R. 214-138 

